Exemplary embodiments of the present invention relate to a safety device for a seat belt, and more particularly, to a safety device for a seat belt, which winds a seat belt upon a collision of a car and provides an operation of unwinding the seat belt when escaping the car, thereby improving the safety of an occupant.
In general, in a car, a safety belt is regarded as a device which most largely contributes for an occupant to survive upon an accident. When a collision of the car occurs, since a pretensioner operates first and tightens a loosely worn seat belt, the occupant may be kept positioned correctly. Since an air bag is deployed after the pretensioner operates, it is possible to minimize a shock applied to the occupant by the air bag.
In the conventional art, because a substantially large tension is applied to the seat belt due to the operation of the pretensioner, difficulties exist in unfastening the seat belt from a buckle after the deployment of the air bag. Therefore, it is demanded to cope with this problem.
The background art of the present disclosure is disclosed in Korean Unexamined Patent Publication No. 2010-0032679 (dated Mar. 26, 2010 and entitled “Lever Crank Type Pretensioner for Seat Belt”)